الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Peach fruit fly, Bactrocera zonata (Saunders) is a serious and destructive pest of horticultural fruits in Egypt, tropical and sub- tropical regions in the world. The pest causes high loss in production annually. The frequent use of chemical insecticides to control this pest resulted many problems such as environmental pollution, pesticide residues on products and possible development of resistant and virulent strains of pest. There is a need in the whole world to develop safe and effective alternative methods for controlling this pest. Bioagents such as entomopathogenic fungi can act as the role of environmentally friend alternative to chemical insecticides. A variety of fungal enzymatic activities can be tested in sample fashion by deterging the ability of culture to grow on specific substrate in defined media.
Some obstacles may appear at this way of application, that the entomopathogenic fungi may reflect different effects on the same pest and on the different stages of the same pest. These differences may be due to biotic or abiotic factors. The idea of combination between entomopathogenic fungi and some compatible insecticides aiming enhancement and strengthening the roll of entomopathogenic fungi in control B.zonata different stages outside fruits is presented in the present work.
1. Entomopathogenic fungal enzymes
- The entomopathogenic fungal isolate, Beauveria bassiana exhibited high activities toward production of the three extracellular enzymes chitinases, proteases and lipases.
- The production of these showed the nature and mode of pathogenicity of the entomopathogenic fungus. The obtained data indicated that enzymatic index value of these hydrolytic enzymes were 42.0mm, 30.6mm and 25mm for chitinases , proteases and lipases production, respectively.
2. Toxicity effect of B.bassiana and M.anisopliae against
peach fruit fly, Bactrocera zonata
- The entomopathogenic fungi, B.bassiana and M.anisopliae showed ability to cause death to peach fruit fly, Bactrocera zonata (Saunders) exposed stages (full-grown larvae, pupae and flies) with superiority of B.bassiana.
- Adult flies were the most susceptible stage to be infected more than full-grown larvae and pupae.
- One-day old pupae showed higher percentages of mortality than four- days old pupae when exposed to both fungi.
- The percentages of larval, pupal and flies mortality were concentration dependent.
3. Scanning electron microscopy
- Scanning electron microscopy cleared the attachment of the B.bassiana conidia on flies body, germination and finally sporulation, which took no more than five days.
4. Effect of combination of B.bassiana and pesticides on larvae of B.zonata and scored malformations.
- Adding sub-lethal doses (quarter-recommended) of the tested insecticides, runner, movento and spincer into the SDA showed no inhibition in B.bassiana vegetative growth.
- The tested insecticides caused mortality full-grown larvae, pupae and flies of B.zonata with preponderance of spincer.
- Some malformations appeared on the use of the tested insecticides as larval-pupal intermediated individuals, black pupae, emerged flies with head only, emerged flies with head and thorax, emerged flies with puparia attached to the abdomen and emerged flies with curly wings.
- Malformed individuals appeared on the application of
B.bassiana-insecticides combinations.
- Combination of sub-lethal doses of runner, movento and spincer with B.bassiana showed synergism and resulted in better percentages of mortality than the use of each alone at the tested stages.
- Biovar 4%WP, the commercial product of B.bassiana based on 2.3×108 conidia/ml, reflected effectivity against tested
stages of B.zonata. In searching of a safe applicable way as possible to control B.zonata, we experimented the use of Biovar4%WP in different concentrations with the lethal and sub-lethal doses of the insecticide, spincer. Biovar4%WP 4grams/L combined with spincer sub-lethal dose (quarter- recommended) resulted the best results in controlling B.zonata.
5. Biochemical studies
- Biochemical studies showed that the larval total protein content increased slightly up to 24 hours of exposure to Biovar4%WP while increased significantly after 7 days. The reverse was true for the larval total carbohydrate content. The larval total lipids content increased significantly up to 24 hours and then decreased after 7 days of exposure to Biovar 4%WP.
- Phenoloxidase activity increased after 24 hours and 7 days of exposure while acetylcholinesterase activity decreased after 24 hours then increased after 7 days of exposure.
- Spincer caused decline of larval total protein and carbohydrates contents at both lethal and sub-lethal doses while reflected slight decrease in total lipids content. A decrease in phenoloxidase activity as well as acetylcholinesterase activity resulted on the use of spincer lethal and sub-lethal doses.